package com.raising.utils;

import javax.servlet.http.HttpServletRequest;
import java.io.PrintWriter;
import java.io.StringWriter;

/**
 * 关于异常的工具类.
 * @author GaoYuan
 * @version 2017-09-26 16:28:55
 */
public class ExceptionsUtils {

	/**
	 * 异常调用方法
	 * @param e
	 * @return
	 */
	public static RuntimeException error(Exception e) {
		e.printStackTrace();
		if (e instanceof RuntimeException) {
			throw new RuntimeException(e);
		} else {
			throw new RuntimeException(e);
		}
//		StringBuffer sb = new StringBuffer();
//		sb.append(e.toString()+"\n");
//		StackTraceElement[] st = e.getStackTrace();
//		for (StackTraceElement stackTraceElement : st) {
//			String exclass = stackTraceElement.getClassName();
//			String method = stackTraceElement.getMethodName();
//			sb.append("[类:" + exclass + "]调用 " + method + " 时在第 [" + stackTraceElement.getLineNumber() + "] 行出错！\n");
//		}
//		LogUtils.saveElog(e.toString(),sb.toString());
//		if (e instanceof RuntimeException) {
//			return (RuntimeException) e;
//		} else {
//			return new RuntimeException(e);
//		}
	}

	/**
	 * 将CheckedException转换为UncheckedException.
	 */
	public static RuntimeException unchecked(Exception e) {
		
		if (e instanceof RuntimeException) {
			return (RuntimeException) e;
		} else {
			return new RuntimeException(e);
		}
	}

	/**
	 * 将ErrorStack转化为String.
	 */
	public static String getStackTraceAsString(Throwable e) {
		if (e == null){
			return "";
		}
		StringWriter stringWriter = new StringWriter();
		e.printStackTrace(new PrintWriter(stringWriter));
		return stringWriter.toString();
	}

	/**
	 * 判断异常是否由某些底层的异常引起.
	 */
	@SafeVarargs
	public static boolean isCausedBy(Exception ex, Class<? extends Exception>... causeExceptionClasses) {
		Throwable cause = ex.getCause();
		while (cause != null) {
			for (Class<? extends Exception> causeClass : causeExceptionClasses) {
				if (causeClass.isInstance(cause)) {
					return true;
				}
			}
			cause = cause.getCause();
		}
		return false;
	}

	/**
	 * 在request中获取异常类
	 * @param request
	 * @return 
	 */
	public static Throwable getThrowable(HttpServletRequest request){
		Throwable ex = null;
		if (request.getAttribute("exception") != null) {
			ex = (Throwable) request.getAttribute("exception");
		} else if (request.getAttribute("javax.servlet.error.exception") != null) {
			ex = (Throwable) request.getAttribute("javax.servlet.error.exception");
		}
		return ex;
	}
	
	
	
	
}
